Sir – Praise in Gray Matter (January 12) for the late Michael Dummett’s charming and quirky little book, Grammar and Style (Duckworth, 1993) was welcome indeed.

However, Michael Dummett’s most important non-technical philosophical work was (is) On Immigration and Refugees (Routledge, 2001), where Dummett’s lifelong ‘especial loathing of racial and its social manifestations’ was powerfully and exactingly set out, philosophically and morally. Dummett laid bare the assumption that immigration is in essence a threat, in the UK and beyond, built as the poisonous seeds of this threat are on crude xenophobia and debasing ethnocentrism, institutional, governmental, and individual, which in practice has led across Europe to the rise of the Far Right and an increasing number of racist attacks.

Professor Dummett’s warning was clear: “Diverse currents swirl about Europe: currents of panic, cruelty and hatred; a strong current of obtuse selfishness, oblivious to its likely consequences; and a current of sanity and humanity.

Only if this last predominates will there be hope of averting disaster for the world outside Europe and within it”.

Sir Michael Dummett shared with an earlier Oxford philosopher, T.H. Green, the “conviction that it was not enough to think but that one must also act” (William Mander: Oxford and British Idealism, Oxford Magazine No. 319, Noughth Week, Hilary Term 2012, p.11). The same conviction should apply to us all.

Bruce Ross-Smith, Headington